An electronic device such as a smartphone and a tablet personal computer (PC) may perform a variety of functions, for example, data communication, sound source playback, video playback, and the like. The electronic device may receive image data from an external device over a network and may output an image based on the received image data. The electronic device may receive and reproduce image data in a download mode or a streaming mode.
If providing additional information using a caption, the electronic device according to the related art may extract a keyword from a previously stored caption file and may provide the additional information associated with the keyword. Various types of keywords may be stored in an external server. If necessary, the electronic device may operate in such a manner to refer to the keyword stored in the server. It is difficult for the electronic device of the related art to perform all computation associated with extracting a keyword and providing additional information. Provided additional information may also be provided on a limited basis in a predetermined form.